advisers, are tasked with the role of identifying the relevant rules, including those set by the
law of armed conflict, and determining how they apply to a particular set of facts. In some
cases, it will be possible to apply a certain rule as it is; while in other cases, the situation may
be conceptually different, such that it might not be possible, feasible, or even desirable to
draw from existing legal rules. This process obviously has to consider the behaviour of
States in the cyber domain, as international law is State-made.
When dealing with a treaty provision, we look to the regular rules of treaty interpretation to
ascertain the relevance and applicability of the provisions at hand in the cyber context. As for
customary law, it is necessary to examine whether there is general State practice accepted
as law, substantiating the existence of a rule in the cyber domain. It cannot be automatically
presumed that a customary rule applicable in any of the physical domains is also applicable
to the cyber domain. The key question in identifying State practice is whether the practice
which arose in other domains is closely related to the activity envisaged in the cyber domain.
Additionally, it must be ascertained that the opinio juris which gave rise to the customary
rules applicable in other domains was not domain-specific. Given the unique characteristics
of the cyber domain, such an analysis is to be made with particular prudence, as it is very
often the case that relevant differences exist.
Since this is the Naval War College’s conference, it is only fitting that I will give an example
from the law of maritime warfare. As you all know, the rules regulating maritime blockade
evolved long ago. Over the years these rules have crystalized into customary law.
Nonetheless, this custom was formed specifically in the maritime context. Putting aside the
question of whether the concept of blockade is relevant to cyberspace, the maritime practice
is not closely related to any type of activity in the cyber domain, while the opinio juris in this
regard is domain-specific. It is therefore quite clear that the rules of maritime blockade are
not applicable in the circumstances of activities in the cyber domain.
The law of neutrality also illustrates the challenges of applying rules that evolved in the
context of traditional warfare to the contemporary environment of cyberspace, as many of its
rules were tailored specifically to the land, sea and air domains. For example, in relation to
one of the basic overarching rules of neutrality – the inviolability of a neutral State’s territory
– while in the land domain it is forbidden to transfer troops or convoys of munition; at sea –
the passage of warships in territorial waters is possible; and in the air such passage is
subject to discretion or limitations of each neutral State. Given these differences, it remains
unclear if and how this rule would be applicable in cyberspace.
These are just examples that show why it is not always easy to move from the general
statement that international law applies to the cyber domain, to concrete legal rules that bind
States and non-State actors in their actual behavior.
Accordingly, the State of Israel has largely refrained thus far from making specific statements
on whether and how particular rules apply. That is not to say that we take no position –
indeed, we have consistently affirmed the application of international law to cyberspace in
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